1. Field of the Invention
The present invention relates to a temperature detector and the method using the same, and more particularly to a temperature detector using a plurality of comparators and the method using the same.
2. Description of the Related Art
Most electronic appliances or components are sensitive to variance of operating temperature. For example, the output performance of digital cameras is significantly affected by the operating temperature. Temperature variation also affects the operating points and operating speed of ICs. To facilitate more stable performance, most electronic appliances use a temperature detector to detect outside temperature and compensate signals accordingly.
FIG. 1 shows a well-known temperature detector. The inputs of a multiplexer 11 are connected to voltage dividers 15, the permutation of which is in a descending order. The output Vres of the multiplexer 11 and the output Vdiode of a diode 14 are used as inputs of a comparator 12. If Vres is greater than Vdiode, the comparator 12 notifies a controller 13 to reduce the value of mul-sel signal of the multiplexer 11 for selecting a smaller Vres in the next iteration. Through several iterations, the controller 13 obtains a Vres value closest to Vdiode. The controller 13 obtains the current IC operation temperature with reference to the ultimum Vres and an internal temperature mapping table.
Current trends show the operating voltages of electronic components have been decreasing, which increases design complexity of a comparator. For example, when the operating temperature of a temperature detector is from −40° C. to 120° C., the voltage variation of the diode voltage is in a range of 0.824 to 0.510. For a comparator design, a low voltage power supply and large input voltage variation will result in extra cost and complexity.